1. Field of the Invention
This invention relates generally to optical imaging devices and methods, and more particularly, provides an adaptor for coupling a video camera to an optical viewing device such as an endoscope, a borescope, or the like, especially for viewing and documenting images from within a patient body.
Endoscopes are often used by physicians to view internal tissues of a patient body. Traditionally, physicians have observed internal body tissues through an eye piece of the endoscope. Although this allows physicians to diagnose and optically direct therapies of these internal tissues, increasingly complex minimally invasive internal surgical procedures have recently been developed, resulting in physicians viewing internal tissues through endoscopes for an extending period of time.
Adaptors have recently become available which attach endoscopes to video cameras, thereby allowing physicians to view images of the internal body tissues on a standard viewing screen. This can significantly increase the comfort of the physician during the procedure, improving both efficiency and safety of endoscopically directed minimally invasive surgical procedures. These adaptors also facilitate documenting the images of the internal tissues (and internal surgical procedures) for future reference.
One disadvantage of known endoscopic video adaptors is that it is often difficult to change the magnification of the video image during the procedure. For example, in laparoscopic cholecystectomy it is generally desirable to begin the surgical procedure while viewing a video image which is at quite low magnification. Low magnification presents a wide, panoramic view of the surgical area, and thereby facilitates optically directing the safe introduction of the various trocars and other instruments which will be cholecystectomy. However, as the cholecystectomy procedure continues, it would be desirable to increase the magnification. More specifically, the surgeon will generally desire a closer, more detailed view when dissecting the cystic artery, dissecting the cystic duct, and when introducing the cholangiogram catheter into the cystic duct. To provide such detailed viewing, quite high magnification of the video image would be desirable. Furthermore, when dissecting the gall bladder from the liver bed, it would be desirable for the surgeon to operate while viewing a video image at a mid-range magnification. In other words, it is generally advantageous to allow a physician to operate at a variety of magnifications during the course of a single surgical procedure. Also, a wide variety of endoscopes with different view angles are used in various surgical procedures. Each scope, however, is required to have a video adaptor with a specific magnification for the video camera to be used. What is necessary, therefore, is a universal zoom video adaptor which can accommodate all endoscope view angles and any camera of choice.
Many video adaptors now being used with endoscopes are restricted to a single magnification level, the adaptors often having a fixed field of view. Video adaptors having some zoom capabilities are available commercially. Unfortunately, these commercially available zoom video adaptors generally require refocusing of the video image each time the magnification has changed. This increases the amount of time required for an endoscopically directed procedure, and can substantially increase patient risk, particularly during the time period the image is out of focus.
To overcome these disadvantages, it would be desirable to provide improved devices for coupling a video camera and/or video system to an endoscopy, borescope, or the like.
2. Description of the Background Art
U.S. Pat. No. 4,862,199 describes an adjustable adaptor for a borescope and a film/video camera. A zoom lens adaptor for an endoscopic camera is described in U.S. Pat. No. 4,781,448. An endoscopic zoom lens is described in U.S. Pat. No. 5,418,645. Optical systems for endoscopes are also described in U.S. Pat. Nos. 5,245,745 and 5,575,757.
An eye piece mechanism for an endoscope is described in U.S. Pat. No. 5,078,503. A lens mount assembly is described in U.S. Pat. No. 5,194,992, while a zoom lens mechanism is described in U.S. Pat. No. 3,906,529. A zoom image coupler is commercially available from Precision Optics Corporation of Gardner, Mass.